A semiconductor memory device includes a memory cell array for storing data information. Data, e.g. 0 or 1, is written in or read out from each memory cell of the array. Read and write operations can be carried out by a read means and a write means, respectively, or by one read/write means depending on a semiconductor memory device. In the case of DRAM devices, for example, read and write operations are carried out through a well-known sense amplifier. In the case of SRAM devices, a read operation is carried out by a sense amplifier and a write operation is carried out by a write driver.
An example of a sense amplifier in a DRAM device is disclosed in U.S. Pat. No. 6,337,823 entitled RANDOM ACCESS MEMORY DEVICE CAPABLE OF MINIMIZING SENSING NOISE. An example of a sense amplifier in a SRAM device is disclosed in U.S. Pat. No. 6,160,747 entitled SEMICONDUCTOR MEMORY WITH AUTO-TRACKING BIT LINE PRECHARGE SCHEME.
Read and write operations consume larger current amounts. This large current consumption decreases a power supply voltage and increases a ground voltage creating a power noise when performing a read or write operation. More particularly, a sensing margin is reduced because of the power noise, decreasing operating speed. Decreasing the operating speed may further drain the power supply voltage.